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12−6
12.6 Latency Timer and Class Cache Line Size Register
The latency timer and class cache line size register is programmed by host BIOS to indicate system cache line size
and the latency timer associated with the SD host controller. See Table 12−5 for a complete description of the register
contents.
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name Latency timer and class cache line size
Type RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW RW
Default 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Register: Latency timer and class cache line size
Offset: 0Ch
Type: Read/Write
Default: 0000h
Table 12−5. Latency Timer and Class Cache Line Size Register Description
BIT FIELD NAME TYPE DESCRIPTION
15−8 LATENCY_TIMER RW PCI latency timer. The value in this register specifies the latency timer for the SD host controller, in units
of PCI clock cycles. When the SD host controller is a PCI bus initiator and asserts FRAME
, the latency
timer begins counting from zero. If the latency timer expires before the SD host transaction has
terminated, then the SD host controller terminates the transaction when its GNT is deasserted.
7−0 CACHELINE_SZ RW Cache line size. This value is used by the SD host controller during memory write and invalidate,
memory-read line, and memory-read multiple transactions.
12.7 Header Type and BIST Register
The header type and built-in self-test (BIST) register indicates the SD host controller PCI header type and no built-in
self-test. See Table 12−6 for a complete description of the register contents.
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Name Header type and BIST
Type R R R R R R R R R R R R R R R R
Default 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0
Register: Header type and BIST
Offset: 0Eh
Type: Read-only
Default: 0080h
Table 12−6. Header Type and BIST Register Description
BIT FIELD NAME TYPE DESCRIPTION
15−8 BIST R Built-in self-test. The SD host controller does not include a BIST; therefore, this field returns 00h when
read.
7−0 HEADER_TYPE R PCI header type. The SD host controller includes the standard PCI header. Bit 7 indicates if the SD host
is a multifunction device.